Crack-cocaine users show differences in genotype frequencies of the dopamine transporter gene (DAT1/SLC6A3) 3′UTR variable number of tandem repeats. - Stolf, Anderson R.; Akutagava-Martins, G.C.; Müller, D.; Guimarães, L.S.; Kessler, F.H.; Pechansky, F.; Roman, T. (Drug & Alcohol Dependence, 2014)